Updated SSI2130 VCO Datasheet available...

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Re: Updated SSI2130 VCO Datasheet available...

Post by thx2112 » Fri Mar 05, 2021 4:36 pm

(Not an LFO)

Here's a SSI2130 VCO in 1U Tile format:

Image

Image

Works great! Can't wait to get into some more complicated VCOs.

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Re: Updated SSI2130 VCO Datasheet available...

Post by adam » Fri Mar 05, 2021 5:10 pm

might as well use a 2131 if you only want saw and tri

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Re: Updated SSI2130 VCO Datasheet available...

Post by thx2112 » Fri Mar 05, 2021 5:58 pm

The 2131 is more DIY friendly too, but it wouldn't fit between the pot/switch/jack pins.

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Re: Updated SSI2130 VCO Datasheet available...

Post by neil.johnson » Fri Mar 05, 2021 6:05 pm

thx2112 wrote:
Fri Mar 05, 2021 4:36 pm
(Not an LFO)

Here's a SSI2130 VCO in 1U Tile format:

Image

Image

Works great! Can't wait to get into some more complicated VCOs.
Very nice compact module. :tu:

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Re: Updated SSI2130 VCO Datasheet available...

Post by neil.johnson » Fri Mar 05, 2021 6:09 pm

If you replace the tri/saw switch with a pot and use the mix out you could cross fade between them.

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Re: Updated SSI2130 VCO Datasheet available...

Post by thx2112 » Sat Mar 06, 2021 12:41 pm

That was the original plan (and it would have been sweet), but two pots and a multi-turn trimmer wouldn't fit together in a row. The multi-turn trimmer for scaling turned out to be essential. A DPDT latching switch fits perfectly with the pot and trimmer though.

I'm working on a double-tile module with almost all the features available.

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Re: Updated SSI2130 VCO Datasheet available...

Post by Neutron7 » Wed Mar 10, 2021 10:22 am

Just a little note: if you use both TZPM and TZFM inputs, dont have the jacks normal switch connected to ground like you "normally" would on an input. It turns the capacitor in to a low pass filter and makes the TZ weak at higher frequencies.

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Re: Updated SSI2130 VCO Datasheet available...

Post by neil.johnson » Wed Mar 10, 2021 10:51 am

Neutron7 wrote:
Wed Mar 10, 2021 10:22 am
Just a little note: if you use both TZPM and TZFM inputs, dont have the jacks normal switch connected to ground like you "normally" would on an input. It turns the capacitor in to a low pass filter and makes the TZ weak at higher frequencies.
Yeah, that would be a problem in a modular synth without input buffers. Not so much of a problem in a monosynth or polysynth where you don't have jacks on the FM inputs.

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Re: Updated SSI2130 VCO Datasheet available...

Post by Neutron7 » Wed Mar 10, 2021 1:05 pm

I tested my prototype with "VCO tuner" This IC's tracking is very impressive, even at high frequencies, you could play synth music for dogs and bats. :lol:
159033700_1161824410928458_4953139767371358326_n.png

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Re: Updated SSI2130 VCO Datasheet available...

Post by lickspittle » Wed Mar 10, 2021 1:37 pm

What do the green error bars show, Neutron7?

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Re: Updated SSI2130 VCO Datasheet available...

Post by Neutron7 » Wed Mar 10, 2021 3:32 pm

lickspittle wrote:
Wed Mar 10, 2021 1:37 pm
What do the green error bars show, Neutron7?
I am not sure, but I think it has something to do with my sound card only having a 48khz sample rate, so it averages each zero crossing time, but shows the max and min. my scope does not have an actual jitter measurement function, but with persistence on, the waves do not get "blurred" so i don't think it is drifting or jittering. (and i don't hear anything like that, either)

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Re: Updated SSI2130 VCO Datasheet available...

Post by lickspittle » Wed Mar 10, 2021 5:03 pm

Noise triggering the zero crossing counter leading to errors which need averaging out? Possibly?

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Re: Updated SSI2130 VCO Datasheet available...

Post by neil.johnson » Wed Mar 10, 2021 5:16 pm

For comparison, here is the SSI2131 (same die as SSI2130, different package) across 11 octaves:
SSI2131-expo-hft.png
Frequency range is about 8 Hz to 17 kHz. These measurements were taken using professional test equipment in an automated test sweep I described earlier in this thread: viewtopic.php?p=3474175#p3474175

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Re: Updated SSI2130 VCO Datasheet available...

Post by bence » Thu Mar 11, 2021 2:25 pm

Hello Neil, maybe you can help me with a problem:)

Upon first powering up my new VCO board i noticed that the VREF was way too low, around 1.7V (I use a 431 with 1k from the +5V rail and all other stuff on the VREF gives a total load around 2k). With 500R between 5V and VREF it was still a tad below, around 2.4V.
Then I noticed that the SINE OUT pad (and as a result also the AUX1 IN, but that is probably not important) was shorted to the VREF pad.
After removing the short the VREF level is now OK, but the VCO still does not oscillate. TCAP pin sits at 0V. The HARD SYNC input has a pulldown as the datasheet suggests. There is around 2uA into the LIN FREQ pin (~1V via 500k). I tried disconnecting the mixer control pins (normally connected via 47k to a control circuit). I also left the bottom pad floating in the design.
I also found that the VREF is loaded more now than it should be, because when restoring the 1k between 5V and VREF, its level went below 2V.

I was wondering if powering up the IC with the VREF below nominal level and/or with a short between VREF and SINE OUT could damage it?
There is also a chance that I killed it with my hand soldering or with ESD, though I don't think so.

Thanks a lot!

bence

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Re: Updated SSI2130 VCO Datasheet available...

Post by neil.johnson » Thu Mar 11, 2021 4:57 pm

bence wrote:
Thu Mar 11, 2021 2:25 pm
Hello Neil, maybe you can help me with a problem:)

Upon first powering up my new VCO board i noticed that the VREF was way too low, around 1.7V (I use a 431 with 1k from the +5V rail and all other stuff on the VREF gives a total load around 2k). With 500R between 5V and VREF it was still a tad below, around 2.4V.
Then I noticed that the SINE OUT pad (and as a result also the AUX1 IN, but that is probably not important) was shorted to the VREF pad.
After removing the short the VREF level is now OK, but the VCO still does not oscillate. TCAP pin sits at 0V. The HARD SYNC input has a pulldown as the datasheet suggests. There is around 2uA into the LIN FREQ pin (~1V via 500k). I tried disconnecting the mixer control pins (normally connected via 47k to a control circuit). I also left the bottom pad floating in the design.
I also found that the VREF is loaded more now than it should be, because when restoring the 1k between 5V and VREF, its level went below 2V.

I was wondering if powering up the IC with the VREF below nominal level and/or with a short between VREF and SINE OUT could damage it?
There is also a chance that I killed it with my hand soldering or with ESD, though I don't think so.

Thanks a lot!

bence
Your VREF resistor is way too high. The circuit load is about 1.35 mA, and the recommended current through the TL431 is 10 mA. That would require a load resistor of 227 ohms. SSI uses 270 ohms or thereabouts.

Damage is always possible, but impossible to predict exactly what went wrong. Did/does the SSI2130 get hot at all?

Neil
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Re: Updated SSI2130 VCO Datasheet available...

Post by bence » Fri Mar 12, 2021 2:25 pm

neil.johnson wrote:
Thu Mar 11, 2021 4:57 pm
bence wrote:
Thu Mar 11, 2021 2:25 pm
Hello Neil, maybe you can help me with a problem:)

Upon first powering up my new VCO board i noticed that the VREF was way too low, around 1.7V (I use a 431 with 1k from the +5V rail and all other stuff on the VREF gives a total load around 2k). With 500R between 5V and VREF it was still a tad below, around 2.4V.
Then I noticed that the SINE OUT pad (and as a result also the AUX1 IN, but that is probably not important) was shorted to the VREF pad.
After removing the short the VREF level is now OK, but the VCO still does not oscillate. TCAP pin sits at 0V. The HARD SYNC input has a pulldown as the datasheet suggests. There is around 2uA into the LIN FREQ pin (~1V via 500k). I tried disconnecting the mixer control pins (normally connected via 47k to a control circuit). I also left the bottom pad floating in the design.
I also found that the VREF is loaded more now than it should be, because when restoring the 1k between 5V and VREF, its level went below 2V.

I was wondering if powering up the IC with the VREF below nominal level and/or with a short between VREF and SINE OUT could damage it?
There is also a chance that I killed it with my hand soldering or with ESD, though I don't think so.

Thanks a lot!

bence
Your VREF resistor is way too high. The circuit load is about 1.35 mA, and the recommended current through the TL431 is 10 mA. That would require a load resistor of 227 ohms. SSI uses 270 ohms or thereabouts.

Damage is always possible, but impossible to predict exactly what went wrong. Did/does the SSI2130 get hot at all?

Neil
Thanks for the answer! :hail:
No, the 2130 is not hot (at least I can't feel it).
Well the datasheet suggests 100uA consumption on the VREF pin, or are you saying 1.35mA including the current of all trimpots and stuff?
Anyway I decreased the resistor and it did not help in this case. Probably the IC is dead or hopefully just missing a few connections on its pads - will try to reflow the joints or replace the IC if the former fails.
On a side note I found that the TL072 forming the TZFM circuitry (datasheet example circuit) gets very hot. After some head scratching I've now realized that the LM311 should have been supplied from the +/-12 rails, not from +5V & GND...:doh:
No wonder the output of the 1st stage was only around -1V (input of LM311 was clamping it hard). Will do some rework:)

best regards,

bence

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Re: Updated SSI2130 VCO Datasheet available...

Post by neil.johnson » Fri Mar 12, 2021 2:45 pm

bence wrote:
Fri Mar 12, 2021 2:25 pm
neil.johnson wrote:
Thu Mar 11, 2021 4:57 pm
bence wrote:
Thu Mar 11, 2021 2:25 pm
Hello Neil, maybe you can help me with a problem:)

Upon first powering up my new VCO board i noticed that the VREF was way too low, around 1.7V (I use a 431 with 1k from the +5V rail and all other stuff on the VREF gives a total load around 2k). With 500R between 5V and VREF it was still a tad below, around 2.4V.
Then I noticed that the SINE OUT pad (and as a result also the AUX1 IN, but that is probably not important) was shorted to the VREF pad.
After removing the short the VREF level is now OK, but the VCO still does not oscillate. TCAP pin sits at 0V. The HARD SYNC input has a pulldown as the datasheet suggests. There is around 2uA into the LIN FREQ pin (~1V via 500k). I tried disconnecting the mixer control pins (normally connected via 47k to a control circuit). I also left the bottom pad floating in the design.
I also found that the VREF is loaded more now than it should be, because when restoring the 1k between 5V and VREF, its level went below 2V.

I was wondering if powering up the IC with the VREF below nominal level and/or with a short between VREF and SINE OUT could damage it?
There is also a chance that I killed it with my hand soldering or with ESD, though I don't think so.

Thanks a lot!

bence
Your VREF resistor is way too high. The circuit load is about 1.35 mA, and the recommended current through the TL431 is 10 mA. That would require a load resistor of 227 ohms. SSI uses 270 ohms or thereabouts.

Damage is always possible, but impossible to predict exactly what went wrong. Did/does the SSI2130 get hot at all?

Neil
Thanks for the answer! :hail:
No, the 2130 is not hot (at least I can't feel it).
Well the datasheet suggests 100uA consumption on the VREF pin, or are you saying 1.35mA including the current of all trimpots and stuff?
Anyway I decreased the resistor and it did not help in this case. Probably the IC is dead or hopefully just missing a few connections on its pads - will try to reflow the joints or replace the IC if the former fails.
On a side note I found that the TL072 forming the TZFM circuitry (datasheet example circuit) gets very hot. After some head scratching I've now realized that the LM311 should have been supplied from the +/-12 rails, not from +5V & GND...:doh:
No wonder the output of the 1st stage was only around -1V (input of LM311 was clamping it hard). Will do some rework:)

best regards,

bence
You told me yourself what the load on the VREF rail is:
(I use a 431 with 1k from the +5V rail and all other stuff on the VREF gives a total load around 2k)
So assuming a VREF of 2.5 V then 2k would sink 1.25 mA alone, plus the 100 uA current into the SSI2130. That is the total load on the VREF line, so that current, plus the knee current of the TL431, needs to flow through the load resistor. Check the data sheet of the TL431 and you see that the rated voltage is specified for a knee current of 10 mA. That's the current that needs to flow through the TL431. You can run it leaner, so lets say a few mA. So 270 ohms ends up being a reasonable choice.

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Re: Updated SSI2130 VCO Datasheet available...

Post by emmaker » Sun Mar 14, 2021 6:15 pm

Here's a question about soldering.

I got some chip carrier boards I'm going to use with the SSI2130. Going to hand solder them to these boards, won't be easy but I can do it.

The issue I have is what flux to use, water soluble or no clean. Don't know if I can clean the boards well enough with the water soluble flux since the chip is pretty snug with the board. There is a hole in the center of the boards to solder a heat sink to, that might get enough water flow under the chip to clean out the flux. With the no clean flux would there be any issues with leaving the flux on the board especially around the critical timing parts (mainly timing cap)?

Thanks, any comments or experiences people could comment on?
Jay S.

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Re: Updated SSI2130 VCO Datasheet available...

Post by oldenjon » Sun Mar 14, 2021 6:32 pm

I think you'd want to clean the 'no clean' flux off the board in this situation too, and you'd run into the same problem. Water soluble flux comes off easier than no clean so I would/do use water soluble. I use an oven for parts like these, but what I would do is try to solder a few pins by hand to get things aligned, then apply flux to the pins/pads for drag soldering. I don't think you'll get much flux under the chip.
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Re: Updated SSI2130 VCO Datasheet available...

Post by oldenjon » Sat Mar 20, 2021 12:13 pm

Just had a look at the SSI2131 datasheet and ordered a sample. Looks like a great chip and modern replacement for CEM3340, but there's one thing that's bugging me. Why is the PWM comparator comparing triangle and not sawtooth? It seems like it's not as versatile this way. You can't for example generate a square in phase with the triangle, or derive a gate for any point in its period.
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Re: Updated SSI2130 VCO Datasheet available...

Post by neil.johnson » Sat Mar 20, 2021 12:20 pm

oldenjon wrote:
Sat Mar 20, 2021 12:13 pm
Just had a look at the SSI2131 datasheet and ordered a sample. Looks like a great chip and modern replacement for CEM3340, but there's one thing that's bugging me. Why is the PWM comparator comparing triangle and not sawtooth? It seems like it's not as versatile this way. You can't for example generate a square in phase with the triangle, or derive a gate for any point in its period.
A PWM derived from the triangle is phase coherent - the pitch doesn't change as the comparator set point is varied. A PWM derived from a sawtooth will suffer/benefit from slight pitch changes as the set point is moved since only one edge of the pulse moves.

You can add an external comparator and drive it from the sawtooth output. Pins are limited and a choice had to be made I guess...
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Re: Updated SSI2130 VCO Datasheet available...

Post by oldenjon » Sat Mar 20, 2021 12:23 pm

Yeah, I knew there must be some logic behind it. Thanks Neil
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Re: Updated SSI2130 VCO Datasheet available...

Post by JanneI » Tue Mar 30, 2021 7:15 am

Hi all! I'll jump in with these testboards. The idea with these is just to make it easier to try out different implementations of this IC. It's not a complete VCO product. If you see something awfully wrong, feel free to comment.
SSI2130testboard.png
SSI2130toDIP.png
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Re: Updated SSI2130 VCO Datasheet available...

Post by kybernetik » Tue Mar 30, 2021 7:51 am

neil.johnson wrote:
Mon Sep 28, 2020 7:03 am
The EXPO FREQ pin is a ground-referenced current input, limited to the range 0 to 200 uA. No negative current. As to what that means depends on the voltage-to-current resistors and the current going into the SCALE pin. The example given in the datasheet is for 20uA/octave (49.9k resistors), which is about the maximum you would want to go. Better would be 10uA/octave (100k resistors) and adjust SCALE accordingly.

Neil
Could you please explain what the danger is of a negative current going into pin 7?

I think in eurorack it's very possible to see a -10v input going into the 1v/oct input, so that's -10v over 100k = -100uA

Would that be a problem? Is there any maximum allowable negative current?

thanks!
- Cosmotronic -

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Re: Updated SSI2130 VCO Datasheet available...

Post by neil.johnson » Tue Mar 30, 2021 8:06 am

JanneI wrote:
Tue Mar 30, 2021 7:15 am
Hi all! I'll jump in with these testboards. The idea with these is just to make it easier to try out different implementations of this IC. It's not a complete VCO product. If you see something awfully wrong, feel free to comment.
Your DIP adaptor looks very similar to the one from SSI, but with the timing capacitor included:
http://www.soundsemiconductor.com/downloads/dab2130.pdf

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